連合
れんごう · rengou · JLPT N2 · noun
union
🔗 連 = link + 合 = join: linked groups joined together make a union
連 means link or chain, and 合 means join or combine. A 連合 is several groups linked and joined into one body, which is the same as a union or alliance.
合 — 乛 (lid/roof) + 口 (mouth)
Originally a pictograph of a lidded vessel — a cover (亼) closing over an opening (口) — giving the core sense of 'come together, join, fit.' From 'fit/match' it extended to 'combine, unite, agree' and to measure-word uses. The reading hé reflects this 'joining' meaning.